Project 1 - Parsing NASA thermodynamic data

Where,

Cp=specific heat

R =molar gas constant

T=temperature

S=Entropy

H=Enthalpy

a=coefficients

 

BODY OF THE CONTENT:

Code for calling function Specific_heat():

function Cp = Specific_heat(a1,a2,a3,a4,a5,a8,a9,a10,a11,a12,T,R,global_midtemp)

%calculating specific_heat for higher and lower temperature respectively

if(T>= global_midtemp)

Cp=R*(a1+(a2*T)+(a3*(T).^2)+(a4*(T).^3)+(a5*(T).^4));

else

Cp=R*(a8+(a9*T)+(a10*(T).^2)+(a11*(T).^3)+(a12*(T).^4));

end

end

 

Code for calling function Enthalpy( ):

function H = Enthalpy(a1,a2,a3,a4,a5,a6,a8,a9,a10,a11,a12,a13,T,R,global_midtemp)

%calculating enthalpy for higher and lower temperature respectively

if(T>=global_midtemp)

H=R*((a1*T)+((a2*(T).^2)/2)+((a3*(T).^3)/3)+((a4*(T).^4)/4)+((a5*(T).^5)/5)+a6);

else

H=R*((a8*T)+((a9*(T).^2)/2)+((a10*(T).^3)/3)+((a11*(T).^4)/4)+((a12*(T).^5)/5)+a13);

end

end

 

Code for calling function Entropy( ):

function S=Entropy(a1,a2,a3,a4,a5,a7,a8,a9,a10,a11,a12,a14,T,R,global_midtemp)

%calculating entropy for higher and lower temperature respectively

if(T>= global_midtemp)

S=R*(a1.log(T)+(a2*T)+((a3(T).^2)/2)+((a4*(T).^3)/3)+((a5*(T).^4)/5)+a7);

else

S=R*(a8.log(T)+(a9*T)+((a10(T).^2)/2)+((a11*(T).^3)/3)+((a12*(T).^4)/4));

end

end

Code for calculating molecular weight by calling function wt( ):

function Molecular_weight=wt(species_name)

Elements=['H' 'C' 'O' 'N' 'A' 'S'];

Atomic_weight =[1 12 16 14 40 32];

species=upper(species_name)

Molecular_weight=0;

for i=1:length(species)

for j=1:length(Elements)

if strcmp(species(i),Elements(j))

Molecular_weight=Molecular_weight+Atomic_weight(j);

k=j;

else

n=str2double(species(i));

if (n>1)

Molecular_weight=Molecular_weight+Atomic_weight(k)*(n-1);

break

end

 

MAIN CODE:

clear all

close all

clc

%R=molar gas constant

R=8.314;

%syntax to open the file THERMO.dat

f1=fopen('THERMO.dat','r')

%To read lines

l1=fgetl(f1);

l2=fgetl(f1);

value=strsplit(l2,' ');

%To get global temperatures from file in number form

global_lowtemp=str2num(value{2})

global_midtemp=str2num(value{3})

global_hightemp=str2num(value{4})

%temperature range

T=linspace(global_lowtemp,global_hightemp,1000);

%skipping these 3 lines

l3=fgetl(f1);

l4=fgetl(f1);

l5=fgetl(f1);

%Reading species ,calcuating cp,h,s and plotting

for i=1:53

tline=fgetl(f1);

A=strsplit(tline,' ');

name_of_species=(A{1});

lowtemp= str2num(A{end-3});

midtemp=str2num(A{end-2});

hightemp=str2num(A{end-1});

%Finding 7 higher coefficients and 7 lower coefficients

tline1=fgetl(f1);

a=findstr(tline1,'E');

a1=tline1(1:a(1)+3);

a1=str2num(a1);

a2=tline1(a(1)+4:a(2)+3);

a2=str2num(a2);

a3=tline1(a(2)+4:a(3)+3);

a3=str2num(a3);

a4=tline1(a(3)+4:a(4)+3);

a4=str2num(a4);

a5=tline1(a(4)+4:a(5)+3);

a5=str2num(a5);

tline2=fgetl(f1);

a=findstr(tline2,'E');

a6=tline2(1:a(1)+3);

a6=str2num(a6);

a7=tline2(a(1)+4:a(2)+3);

a7=str2num(a7);

a8=tline2(a(2)+4:a(3)+3);

a8=str2num(a8);

a9=tline2(a(3)+4:a(4)+3);

a9=str2num(a9);

a10=tline2(a(4)+4:a(5)+3);

a10=str2num(a10);


tline3=fgetl(f1);

a=findstr(tline3,'E');

a11=tline3(1:a(1)+3);

a11=str2num(a11);

a12=tline3(a(1)+4:a(2)+3);

a12=str2num(a12);

a13=tline3(a(2)+4:a(3)+3);

a13=str2num(a13);

a14=tline3(a(3)+4:a(4)+3);

a14=str2num(a14);

%calculate specific heat(cp),Enthalpy(H),Entropy(S)

Cp=Specific_heat(a1,a2,a3,a4,a5,a8,a9,a10,a11,a12,T,R,global_midtemp);

H=Enthalpy(a1,a2,a3,a4,a5,a6,a8,a9,a10,a11,a12,a13,T,R,global_midtemp);

S=Entropy(a1,a2,a3,a4,a5,a7,a8,a9,a10,a11,a12,a14,T,R,global_midtemp);

%calculating molecular weight and printing it.

Molecular_weight=wt(name_of_species);

fprintf('molecular weight of %s= %f\n',name_of_species,Molecular_weight);

%PLOTTING CP,H,T

cd('C:\Users\hhh\Desktop\matlab\NASA FILES')

%creating the folder

mkdir(name_of_species);

cd(name_of_species);

%plotting T vs cp

figure(1)

plot(T,Cp,'linewidth',5,'color','r')

xlabel('Temperature(T)')

ylabel('Specific heat(cp)')

grid on

title(name_of_species)

saveas(figure(1),'specific heat.jpg');

%Plotting T vs H

figure(2)

plot(T,H,'linewidth',5,'color','b')

xlabel('Temperature(T)')

ylabel('Enthalpy(H)')

grid on

title(name_of_species)

saveas(figure(2),'Enthalpy.jpg');

 

%Plotting T vs S

figure(3)

plot(T,S,'linewidth',5,'color','y')

xlabel('Temperature(T)')

ylabel('Entropy(S)')

grid on

title(name_of_species)

saveas(figure(3),'Entropy.jpg');

cd('C:\Users\hhh\Documents\MATLAB\nasa files')

end

 

Explanation for code:

Initially the value of ‘R’ is being defined.

Then we use a command to open the file ‘THERMO.dat’ .

Further we use the ‘fgetl’ to start reading the lines and after reading the first two lines, from the second line converting the

strings to numbers and assigning global (low,mid and high) temperatures.

Then we have written a command to get the temperature range for calculation and plotting purpose.

Then again using the fgetl command to go to thel next 3 lines and skipping it.

Then we use a for loop to get 53 species and their temperatures (low, mid, high) and the 14 coefficients.

In the for loop we again use the fgetl command and then the next line is read and from that line the species name, the three

local temperatures are read and stored.

Then we use fgetl command to go to further line and get the first 7 coefficients and store them. Similarly using the fgetl

command we move to the next two lines and get the remaining coefficients.

Then after getting the 14 coefficients, we use these coefficients and by calling the functions we calculate cp,H,S.

Further we use the Molecular weight function and calculate molecular weight for that species.

Further I have used a command to change the directory so that I can save the files at a particular location.After changing the

directory I have used ‘mkdir' to create a new folder with the name of the current species and then a ‘cd’ command to make

mkdir as the current directory.

Then further we use plot command to plot temperature vs (cp,enthalpy,entropy) .

In this plotting we use the figure command to get the three different plots and saveas command to save the figures in the

Then again we change our directory to again start the loop. So the loop continues to function till we get all the 53 species

and then gets terminated.